The Montreal Protocol for the protection of the ozone layer mandates the phase out of the use of chlorofluorocarbons (CFCs). Materials more “friendly” to the ozone layer such as hydrofluorocarbons (HFCs) e.g. 134a replaced chlorofluorocarbons. The latter compounds have proven to be greenhouse gases, causing global warming and could be regulated by the Kyoto Protocol on Climate Change. Replacement materials are needed which are environmentally acceptable i.e. have negligible ozone depletion potential (ODP) and acceptable low global warming potential (GWP). The present invention describes a process for manufacturing of the hydrofluoropropene HFO-1234yf which is useful as a low ODP and low GWP blowing agent for thermoset and thermoplastic foams, solvent, heat transfer fluid or refrigerant such as a mobile air conditioner systems.
US patent publications US2008/0051610 and US2008/0103342 disclose a process that includes a step of the catalytic isomerization of cis 1234ze to trans 1234ze. U.S. Pat. No. 7,420,094 discloses the isomerization of 1234ze to 1234yf with a Cr based catalyst.